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A novel core-shell nanomaterial, ZnO nanoparticles (NPs), and a shell-core ZnO@SiO 2 using extracts from Calligonum comosum L. leaves successfully fabricated. The investigation focuses on evaluating the photocatalytic efficiency of the produced catalyst against organic pollutants. SiO 2 NPs, ZnO NPs, and shell-core ZnO@SiO 2 structures exhibit spherical morphologies with average diameters of approximately 25–50 nm, 50–100 nm, and 35–65 nm, respectively. SiO 2 NPs possess an amorphous structure, while ZnO NPs, SiO 2 NPs, and the ZnO shell exhibit crystalline arrangements, featuring average crystallite sizes of 32.8 nm, 62.3, and 13.5 nm, respectively. Band gap energies are determined to be 3.6 eV, 2.3 eV, and 2.15 eV for SiO 2 NPs, ZnO NPs, and ZnO@SiO 2 nanocomposite, respectively. Catalytic performance is evaluated using Methylene Blue (MB) as a cationic dye and Rose Bengal (RB) as an anionic dye. Remarkably, the shell-core ZnO@SiO 2 nanocomposite achieves degradation efficiencies of 99.3% for MB and 98.0% for RB, surpassing ZnO NPs with degradation coefficients of 86.6% for MB and 91.7% for RB. These degradation processes occur under solar light irradiation, at a contact time of 120 min, pH 7, and temperature of 25 °C. The study underscores the potential of the ZnO@SiO 2 nanocomposite as an effective, cost-efficient, and environmentally friendly solution for water treatment. Graphical abstract

The phytochemical constituents of Calligonum tetrapterum Jaub. & Spach (Family Polygonaceae) were studied for the first time. The study resulted in the isolation of the rare flavonol glycoside, kaempferol 3-O-(6″-O-acetyl)-glucoside,(K3G-A). The potential inhibitive activity of K3G-A toward SARS-CoV-2 was investigated utilizing several in silico approaches. First, molecular fingerprints and structural similarity experiments were carried out for K3G-A against nine co-crystallized ligands of nine proteins of SARS-CoV-2 to reveal if there is a structural similarity with any of them. The conducted studies showed the high similarity of K3G-A and remdesivir, the co-crystallized ligand of SARS-CoV-2 RNA-dependent RNA polymerase (PDB ID: 7BV2), RdRp. To validate these findings, a DFT study was conducted and confirmed the proposed similarity on the electronic and orbital levels. The binding of K3G-A against RdRp was confirmed through molecular docking studies exhibiting a binding energy of −27.43 kcal/mol, which was higher than that of remdesivir. Moreover, the RdRp-K3G-A complex was subjected to several MD studies at 100 ns that authenticated the accurate mode of binding and the correct dynamic behavior. Finally, in silico ADMET and toxicity evaluation of K3G-A was conducted and denoted the safety and the drug-likeness of K3G-A. In addition to K3G-A, two other metabolites were isolated and identified to be kaempferol (K) and β-sitosterol (β-S).

Moisture is the most important environmental factor limiting seed regeneration of shrubs in desert areas. Therefore, understanding the effects of moisture changes on seed germination, morphological and physiological traits of shrubs is essential for vegetation restoration in desert areas. In March to June 2023, in a greenhouse using the potting method, we tested the effects of soil moisture changes (5%, 10%, 15%, 20% and 25%) on seed germination and seedling growth of six desert shrubs (Zygophyllum xanthoxylum, Nitraria sibirica, Calligonum mongolicum, Corethrodendron scoparium, Caragana korshinskii, and Corethrodendron fruticosu). Results showed that (1) seed germination percent and vigor index were significantly higher at 15 and 20% soil moisture content than at 5 and 10%; (2) shoot length, primary root length, specific leaf area and biomass of seedlings were significantly higher in the 15% and 20% soil moisture content treatments than in the 5% and 10% treatments; (3) superoxide dismutase activity (SOD) and soluble protein content (SP) decreased with decreasing soil water content, while peroxidase activity (POD) and catalase activity (CAT) showed a decreasing and then increasing trend with increasing soil water content; (4) the six seeds and seedling of shrubs were ranked in order of their survivability in response to changes in soil moisture: Caragana korshinskii > Zygophyllum xanthoxylum > Calligonum mongolicum > Corethrodendron scoparium > Corethrodendron fruticosu > Nitraria sibirica. Our study shows that shrub seedlings respond to water changes by regulating morphological and physiological traits together. More importantly, we found that C. korshinskii, Z. xanthoxylum and C. mongolicum were more survivable when coping with water deficit or extreme precipitation. The results of the study may provide a reference for the selection and cultivation of similar shrubs in desert areas under frequent extreme droughts in the future.

Understanding the climatically suitable habitat of species plays a vital role in the sustainable use and management of target species. Calligonum mongolicum Turcz., a native shrub species found in desert areas of Central Asia, is generally considered as one of the top four tree species for desertification control. However, previous works on suitable habitat simulation had focused mainly on either the national or specific geographical scales rather than entire biota scales, which have underestimated the climatic tolerance of the species. Furthermore, the uncertainty outcomes of climate change were largely ignored. With these questions, the arid regions of Central Asia were selected as our research background area. Occurrence data of C. mongolicum were obtained from various sources, such as the Global Biodiversity Information Facility, the Chinese Virtual Herbarium, and the iPlant website. The maximum entropy model (MaxEnt) was used to simulate the suitable habitat change dynamics under various climate change scenarios [5 general circulation models (GCMs) × 3 shared socioeconomic pathways (SSPs)]. The uncertainty of climate change induced by GCMs and SSPs were decomposed by the two-way ANOVA method. Our results show that hydrological-related variables are more important for the species’ habitat suitability than thermal-related variables. The climatic threshold for the core suitable habitat was 1–30 mm for precipitation of the coldest quarter, 14–401 mm for annual precipitation, −16.01–12.42 °C for mean temperature of the driest quarter, 9.48–32.63 °C for mean temperature of the wettest quarter, and −25.01–−9.77 °C for the minimum temperature of the coldest month. The size of suitable habitat was about 287.4 × 104 km2 under the current climate condition, located in China and Mongolia. Climate change has less impact on the total area size, but it has bigger impacts on the gain area and loss area sizes. The loss area is mainly located in the southeast boundaries, whereas the gain area is mainly located in Mongolia and the Qinghai-Tibet Plateau. The decomposition uncertainty of climate change indicates that GCMs could explain 14.5%, 66.4%, and 97.0% of total variation, respectively, and SSPs could explain 85.5%, 33.6%, and 3.0% of the total variation for gain, loss, and total habitat sizes, respectively. Our work clearly demonstrates that while C. mongolicum has great planting potential in Central Asia under various climate change scenarios, the sensitive areas possess large uncertainties requiring long-term climate monitoring for afforestation projects.

Two extraction schemes, conventional and high-pressure extraction methods were applied on Calligonum azel Maire leaves and roots, with purpose to exploit this plant as a source of natural antioxidants. The total phenolic content (TPC), trolox equivalent antioxidant capacity (TEAC) of extracts, and solid materials were determined. Varying yields of active fractions were obtained by consecutive extractions with increasing polarity solvents. In the Soxhlet extraction, the highest antioxidant capacity values were obtained with methanol, while in the pressurized liquid extraction (PLE), the highest TEAC was recorded in acetone extracts for both materials. The changes of antioxidant indicators of solid plant materials during the extraction were studied by the so-called QUENCHER method (QU: quick, E: Easy, N: New, CHE: Cheap, and R: Reproducible). In this case, TPC varied in the range of 2.3–60.5 expressed in mg gallic acid equivalent per gram of dry weight of plant (mg GAE/g DWP), while radical scavenging capacity was 1.7–75.4 micromole Trolox equivalent per gram of dry weight of plant material (µmol TE/g DWP). All extracts were analysed by ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry and the results showed thirteen compounds including flavonoids. The essential oils extracted by hydrodistillation, were screened by gas chromatography–mass spectrometry and the results showed the presence of 82 and 55 compounds in C. azel leaves and roots, representing 97.6% and 83.4% of the oil, respectively, while in the supercritical fluid extraction using CO2, both materials showed 52 and 50 compounds, representing over 98.7% and 71.5% of the oil.

Calligonum polygonoides L. (Phog) is an endemic perennial herb that is highly resistant to all type of abiotic stresses and dominant biomass as well as phytochemicals producer in its natural habitat of the “Thar Desert” of Rajasthan, India. The present study was conducted to evaluate the effect of extreme environmental conditions on the phenolic, flavonoids, tannin content, and total antioxidant activities of C. polygonoides foliage harvested during different months. It exhibited a significant variation in the content of phenolic compounds, flavonoids, tannins, and antioxidant activity with harvesting time and all parameters are positively correlated to each other. The highest phenolic compounds and antioxidant activity was observed during severe winter and summer months, when monthly average environmental temperature was lowest and highest of the year, respectively. On the basis of the results, two harvests of C. polygonoides foliage during June and December are advised to maximize the phenolic compound production with highest antioxidant activity. These results demonstrate C. polygonoides, which is a dominant biomass producer under the harsh climatic conditions, can be an important source for the development of the functional foods rich in antioxidants in hot arid regions.

Medicinal herbs are potential sources of biomolecules and their analogues that have great relevance in the preparation of modern medicines. Calligonum crinitum, a perennial shrub growing in the United Arab Emirates, has been utilized in the study to validate the therapeutic properties exploited in the traditional medicinal system of UAE. The phytochemical screening of the plant employing different solvents of methanolics and ethyl-acetates, expressed varied proportions of monosaccharides and carbohydrates along with tannins and saponins, which are high potency molecules for therapeutic applications. The presence of total phenol and flavonoid contents derived from methanolic extracts indicates antioxidant potentials and the defense mechanisms of the plant. Proximate and mineral nutrient analysis validates the significance of the extracts with a high amount of carbohydrates and proteins along with significantly high amounts of Zn, Fe, Mn, Ca, Mg and K involved in various metabolic reactions. Similarly, the ABTS radical scavenging activity varied significantly (p < 0.05) and ranged from 10 to 160 µg GAE/g in the methanolic extract. DPPH free radical scavenging activity exhibited a significantly high DPPH activity in methanolic extracts with free radical scavenging activity of 72%. Hydroxyl radicals scavenging activity was also found to be high in the Calligonum extracts along with SOD (49–83%, compared to the standard GAE 37–58%). Nitric oxide scavenging was also found to be high in the extracts, thereby decreasing the content of NO. Thus, our results confirm that the derived extracts have potential antioxidants, and this legitimizes their use in folkloric medicine. These results are highly significant as they can pave the way for future scientific validation of the traditional knowledge of this important medicinal plant.

Background Calligonum (Polygonaceae) is distributed from southern Europe through northern Africa to central Asia, and is typically found in arid, desert regions. Previous studies have revealed that standard DNA barcodes fail to discriminate Calligonum species. In this study, the complete plastid genomes (plastome) for 32 accessions of 21 Calligonum species is sequenced to not only generate the first complete plastome sequence for the genus Calligonum but to also 1) Assess the ability of the complete plastome sequence to discern species within the group, and 2) screen the plastome sequence for a cost-effective DNA barcode that can be used in future studies to resolve taxonomic relationships within the group. Results The whole plastomes of Calligonum species possess a typical quadripartite structure. The size of the Calligonum plastome is approximately 161 kilobase pairs (kbp), and encodes 113 genes, including 79 protein-coding genes, 30 tRNA genes, and four rRNA genes. Based on ML phylogenetic tree analyses, the complete plastome has higher species identification (78%) than combinations of standard DNA barcodes ( rbcL  +  matK  + nrITS, 56%). Five newly screened gene regions ( ndhF , trnS-G , trnC-petN , ndhF-rpl32 , rpl32-trnL ) had high species resolution, where ndhF and trnS - G were able to distinguish the highest proportion of Calligonum species (56%). Conclusions The entire plastid genome was the most effective barcode for the genus Calligonum , although other gene regions showed great potential as taxon-specific barcodes for species identification in Calligonum .

Understanding plants responses to drought stress is crucial for selecting appropriate species for shelter-forest construction in arid and semi-arid regions. Calligonum caput-medusae , one of the most planted shrubs along the Taklimakan Desert Highway Shelterbelt (TDHS), contributes significantly to maintaining the highway’s ecological stability. This study aimed to investigate the physiological responses of biennial C. caput-medusae seedlings to drought stress by monitoring changes in soil moisture and chlorophyll fluorescence parameters [actual photo chemical efficiency of PSII (Y (II) ), unregulated energy dissipation quantum yield (Y (NO) ), non-photochemical quenching coefficient (NPQ), and regulatory energy dissipation quantum yield (Y (NPQ)) ] under controlled conditions. The results showed that soil moisture declined progressively with prolonged drought stress. Although the photosystem II (PSII) reaction centers of the seedlings experienced some stress after 30 days of drought, no irreversible photodamage occurred. However, the risk of photoinhibition and damage to the photosynthetic apparatus increased with prolonged drought, as evidenced by an increase in NPQ. These findings suggest that C. caput-medusae seedlings adapt to drought stress by modulating their chlorophyll fluorescence characteristics, enhancing our understanding of its drought adaptation mechanisms and highlighting the need for future research on its long-term physiological responses under field conditions and varying drought intensities.

The species is a typical shrub with assimilative branches (ABs) in arid regions in Central Asia. The nutrient distribution patterns at different reproductive stages are of great significance for further understanding the ecological adaptation and survival strategies of plants. In the present study, a common garden experiment was employed to avoid interference by environmental heterogeneity. Furthermore, the nitrogen (N), phosphorus (P), and potassium (K) allocation characteristics in the supporting organs (mature branches), photosynthetic organs (ABs), and reproductive organs (flowers and fruits) of (CC), (CA), (CR), and (CK) during the flowering, unripe fruit, and ripe fruit phases were systematically analyzed. Aboveground organs were the main factors affecting the variation of N, P, and K concentrations and their stoichiometric ratios, and the reproductive stages were secondary factors affecting N, P, and the P:K ratio and species were secondary factors affecting K and the N:P and N:K ratios. Meanwhile, significant interactions were found for all three of the aforementioned factors. The N and P concentrations in the ABs of the four species were highest during the flowering phase, while the N:P ratio was lowest, which then gradually decreased and increased, respectively, during plant growth. This result supported the growth rate hypothesis, i.e., that the growth rate is highest during the early growth stage. In the growth period, the N, P, and K concentrations in each organ of the four species followed the power law, with the allocation rates of N and P being generally higher than K. There were differences among the species as the N-P scaling exponent in the ABs of CR was only 0.256; according to the scaling exponent law, this species was the least stressed and had the strongest environmental adaptability. Overall, the adaptability of the four species could be ranked as CR > CA > CC > CK. In conclusion, there were significant differences in nutrient traits among different aboveground organs, species, and reproductive stages. The results of this study contribute to a deeper understanding of the nutrient allocation strategies of different species and provide scientific evidence for the conservation and fixation application of these species.